Generally, in the case of thermoplastic synthetic fibers such as polyester, nylon, polypropylene, etc., an oiling agent for treating fibers is attached to unstretched filaments, followed by stretching to 4 to 5 times the original length and heat-set for fixing the properties. The resulting stretched filaments are further passed through advanced processing steps such as bulky processing, twisting, warping, knitting, weaving, etc. to give fiber products, and in such production step and processing step, filaments are industrially very often treated at considerably high speed and temperature; thus, various obstacles due to static electricity generated by such speed-up of production and processing, such as filament splitting, jumping-out from filament path, filament swing on heater, twining round roller, etc. have become a more and more serious problem. In order to diminish such obstacles and thereby carry out the production and processing with good efficiency, an oiling agent for treating fibers has been required which reduces static electricity generated on filaments due to friction as much as possible, further imparts a large extent of lubricating property onto filaments and does not contaminate heater so much.
As antistatic agents used for fiber-treating oiling agents, various kinds of ionic surfactants have so far been proposed, but it is pointed out that for the speed-up of the steps, and particularly under severe conditions of high temperature, high tension, high speed, etc., they have not been yet provided with fully satisfactory performances for various required characteristics as mentioned below.
Namely, under conditions of speed-up and higher temperature of the production and processing, such problems as (1) increase in frictional static build-up voltage, (2) deposition of tar onto heater and (3) increase in frictional coefficient are liable to be raised, and this results from inhibition of performances due to antistatic agent added to the fiber-treating oiling agent, inadequate choice of antistatic agent, its excess amount added, etc.